Water-cooled multicircuit magnetron



9 m. m w .e-n 5 ON 2, t5 o n .t ed .t w Vw A m 1mm@ m .n H. M Nmw QW.Owl mm2, z NUM im Rmm mm.. m Q 9 m MO n sept. 19, 1950 Patented Sept.1.9, 1950 UNITED STATES PATENT. OFFICE WATER-COOLED MUL'TICIRCUITVMAGNETRJON Richard B. Nelson, Schenectady, N. Y., assignor toGeneralElectric Co'mpan a corporation of New York Application October 2,1946, Serial No. 700,758

11 Claims.

My invention relates specifically to Water cooled vane type magnetronsand more generally to improved electric discharge devices of themagnetron type.

Magnetron devices including a plurality of coupled resonant circuits asan anode structure, have been developed for high frequency applications.My invention relates to an improved device of this character which is?particularly adapted for high power continuous wave applications and isWell suited for industrial applications such as dielectric heating.ter-:ine my invention contribute to a device which is rugged, relativelyyeasy to manufacture, and wl'iich is easily connected with `the highirequency cil .uits with which it is used.

It is an object of my inventionto provide al new and improved electricdischarge ldevice ofA the magnetron type.

It is another object of my invention to provide a new and improvedresonant structure for electric discharge devices. A

For a` better understanding of my invention,

reference may be had to the following descrip-vr envelope I whichlmay toadvantage be forme of copper or .other material which is essentiallynonmagnetic. A circular array of anode elements 2 rto II, inclusive, aresupported from the inner wall of envelope l in uniformly spaced radialrelation. Each of the elements is, in the preferred embodiment,illustrated of substantially Usliaped in a radia plane and is` formedfrom rod-like st ck such as copper tubing. As illustrated in Fig. l, theopen ends of the arms of each. Uasl'iapt-:d anode section communicatewith IZ and I3 formed in the wall of the envelope. in order to'kfacilitate manufacture, passages I2 and I3 areI formed by machining thecylindrical recesses in the' outer wall of the copper cylinder, and thencompleting the` passages by bracing to the envelope a sheet metalcylinder Id. As illustrated in Fig. 1, the upper passagev l2'communicates `with the fitting l5 through a longitudinal passage IS. Asimilar fluid passage I3! communicating with the cir-'f The featureswhich charac` trode space.

complete a iluid circuit through the various anode sections.

In addition to providing for the eflicientfcool-y ing of the anodestructiue, the particular form of the anode elements described alsopermits strapping of the anode in an improved manner. As illustrated inthe drawing, a pair of ring straps El and i8 surround the longitudinalor portion of each U-shaped'ianode element. Strap I'i is electricallyconnected, as by brazing,

to each alternate anode section and strap I3 is j connected with theremaining anode sections. illustrated in Fig. 2, the strap I3 isconnected' with the anode sections 3, 5, l, S and II.

ance connections between the interconnected anode sections and alsominimizes the electrical dissymmetry usually produced by doublestrapping structures. As distinguished from usual types of ringstrappingthe rings of the present invention both of the same diameterand are shielded from the cathode to a considerable extent by the :baseportions of the anode sections. near the axial center of the anodesections and symmetricallyvwith respect to the cathode pro? a helicalcathode i9 lccatedcentrally in the open?v ing supported from theenvelope I by means including a terminal and lead-in structure. Asillustrated in Fig. l, the upper end wall of the envelop@ is provided byan apertured metal member EEE which is in the shape of a truncated 44)'cone directed inwardly of the envelope. The member il@ is formed ofmaterial having low magnetic reluctance and in addition to providing aportion of the envelope provides a pole piece for producing a magneticfield in the interelecf A sheet metal disk or washer 2i isr secured tothe exterior of the member 2li and pro vided with upstanding anges 22and 23. The outer flange is bonded to the inner wall of the envelope toposition and hermetically seal the pole piece to the envelope. The innerflange 2t is joined to a anged member 24 which surrounds the aperture inthe pole piece 21| and provides a support for the cathode lead-intermi-v nals. As illustrated. an inner flange r25 on the member 24 issealed to the lower edge of a cylinn Thisr 5arrangement' of strapsprovides very low lipped Also, the location of the rings' dricalinsulator 26. A metal sleeve y21, which provides one terminal for thefilamentary cathode I9, is sealed to the upper edge of the insulatingcylinder 26. The other terminal for the cathode is provided by acylindrical member 28 closed at its outer end and sealed to the terminal2'| by a cylindrical insulator 29. The upper terminal of the cathode isconnected directly to the terminal 28 by an elongated conducting stud 39Which is bonded to the inner end wall of the terminal 28. Asillustrated, this stud is substantially smaller in diameter than theinsulating cylinder 26 to permit the connection of the other terminal ofthe cathode I9 with the sleeve terminal 2`| by means of a conductingcylinder 3| interposed between the stud 3G and the insulator 26. Asillustrated in the drawing, the lower terminal of the cathode isconnected with a conducting end shield 33 which is, in turn, connectedby a central post at 32 to an upper end shield 34. The upper end shieldis connected with the cylinder 3| and as a result with the externalterminal 27 by a conductor 35.

A vpole piece similar to the member 20 is provided directly below theanode structure by a member 36 of frusto-conical shape. This member isbonded to the inner wall of the envelope with the flattened centralportion adjacent the interelectrode space. The members 2U and 35cooperate with a coil 31 which surrounds the envelope to produce amagnetic lield between the anode and cathode which is substantiallyparallel to the axis of the cathode. It will be apparent that the wallof the envelope provides a magnetic shunt with respect to theinterelectrode space, and for this reason it is desirable to utilize amaterial of high magnetic reluctance for the envelope and to provide amagnetic yoke 3'1 about the coil which terminates opposite the members20 and 3S.

The envelope of the device is completed by a seal construction whichprovides concentric terminals for connection with an external highfrequency circuit. A cup-shaped metal terminal 38 is supported centrallywithin the envelope and sealed thereto by a dome-like insulator 38 whichis sealed at its lower edge to a cylindrical sheet metal member 40. Themember 4Q terminates at its lower end in a ange 4| which ts Within acylindrical extension of the envelope provided by a sheet metal ring 42.The llange 4| and ring 42 are bonded together to hermetically seal theenvelope and support the sealing structure within the metal cylinder Thecentral terminal 38 is conductively connected by a strap 43 with one ofthe anode sections 6. As illustrated, this strap extends through anopening 44 in the pole piece 36. The cup-shaped terminal 38 and the ring42 provide concentric terminals which are adapted to connect themagnetron device with a concentric transmission line, through which thepower produced by the device is conducted to a suitable load.

As will be readily understood by those skilled in the art, highfrequency oscillations are produced by exciting the resonant structureprovided by the various anode sections by means of a space chargeproduced in the region between the inner ends of the anode sections andthe cathode and moving under the combined action of an electric eldproduced by voltage applied between the anode and cathode, and the axialmagnetic eld produced in the interelectrode space by coil 31 andcooperating pole pieces 2| and 36. It will be apparent from thedescription that the illustrated embodiment of my invention provides amagnetic device which is of relatively simple structure, which isadapted to be water-cooled, and which is easily plugged into both thecoil for producing a magnetic field and the concentric terminals of anoutput circuit.

While I have shown and described a particular embodiment of myinvention, it will be obvious to those skilled in the art that changesand modifcations may be made without departing from my invention in itsbroader aspects, and I, therefore, aim in the appended claims to coverall such changes and modifications as fall within the true spirit andscope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. In a magnetron device of the resonator anode type, an anode structureincluding a cylindrical supporting envelope, a plurality of anodesections supported from the inner wall of said envelope and extendingradially inwardly in circumferentially spaced relation, each of saidanode sections comprising bent tubing having a substantially U-shapedsection in a radial plane and having the open ends of the tubing of eachsection communicating with passages in the Walls of the envelope, and apair of conducting rings threading the openings provided by said U-shaped anode sections, each being electrically connected with differentalternate anode sections.

2. In a magnetron device of the resonator anode type, an anode structureincluding a cylindrical supporting envelope, a plurality of anodesections supported within said envelope and extending radially -inwardlyin circumferentially spaced relation and providing a plurality of cavityresonators, each of said anode sections comprising bent tubing' having asubstantially U-shaped section in a radial plane and each having thearms thereof extending outwardly, and means supported from the side wallof said envelope providing passages communicating with the outwardlyextending open ends of the tubing forming said sections. v

3. In a magnetron device of the resonator type, an anode structureincluding a cylindrical supporting envelope, an even number of anodesections supported within said envelope and extending radially inwardlyand in circumferentially spaced relation, each of said anode sectionscomprising bent tubing having a substantially U- shaped section in aradial plane, said sections having the base'portions thereof extendingin an axial direction and in circumferentially spaced relation anddening a central opening of the anode structure, and a pair ofconducting rings threading the openings provided by said U-shaped anodesections, one of said rings being connected with the even number anodesections on the side of the base portions away from the central openingand the other of said rings being connected with the odd numbered anodesections on the side of the baseportions away from the central open;ing.

4. In a magnetron device of the resonator anode type, a cathode, ananode structure comprising a plurality of anode sections extendingradially inwardly in circumferentially spaced relation to provide acircular array, each of said anode sections having an aperturetherethrough which is symmetrical with respect to a central planethrough said anode transverse to the axis of the circular array, and apair of conducting rings threading said apertures with each ring on adiilerent side of said central plane with a portion of each of saidanode sections interposed between said rings and said cathode, one ofsaid rings being connected with alternate anode sections and the otherof said rings being connected with the remaining anode sections.

5. In a magnetron device of the resonator anode type, an anode structurecomprising a plurality of anode sections, a support, said anode sectionsbeing mounted within said support and extending radially inwardly toprovide a circular array of anode sections, each of said sections havingan aperture therethrough dei-med in part by axially extending portionsat the inner ends of the anode section, and a pair of conducting ringsof equal diameters threading said apertures with each ring positioned onopposite sides of a plane extending through said anode structure at thelongitudinal center thereof and in a direction perpendicular to thelongitudinal axis thereof, one of said rings being connected with theaxially extending portions of alternate anode sections on the sidesthereof facing said apertures and the other of said rings beingconnected with the axially extending portions of the remaining anodesections on the sides thereof facing said apertures.

6. In a magnetron device of the resonator anode type, an anode structurecomprising a plurality of anode sections extending radially inwardly incircumferentially spaced relation7 each of said sections having anaperture therethrough, said apertures being dened in part by axiallyextending portions of said anode sections located at the inner endsthereof, and a pair of conducting rings threading said apertures andpositioned on opposite sides of a plane passing through the center ofsaid anode sections in a direction perpendicular to the axis thereof,one of said rings being connected to the axially extending portions ofalternate anode sections on the side thereof facing said apertures, andthe other of said rings being connected with the axial portions of theremaining anode sections on the side thereof facing the aperturestherethrough.

7. In an electric discharge device of the magnetron type comprising agenerally cylindrical envelope, an anode structure supported within saidenvelope intermediate the ends thereof and including a plurality ofcircumferentially displaced cavity resonators, an end wall for saidenvelope including a pole piece, a second pole piece supported on theopposite side of said anode structure within said envelope and a closureat the other end of said envelope including a concentrically locatedterminal and an annular sealing member housed within said envelope andmeans extending through said second pole piece coupling ,said centralterminal with said anode structure. a

8. In an electric discharge device of the magnetron type comprising agenerally cylindrical envelope, an anode structure supported within saidenvelope intermediate the ends thereof and including a plurality ofradially extending anode sections dening a plurality ofcircumferentially displaced resonator elements, an end wall for saidenvelope including a pole piece, a second pole piece supported from saidenvelope on the opposite side of said anode structure within saidenvelope and a closure for the other end of said envelope including aconcentrically located ter- Iii minal and an annular sealing memberlocated on the side of said second pole piece remote from said anode andhoused within said envelope, and means coupling said central terminalwith said anode structure.

9. In an electric discharge device of the magnetron type comprising agenerally cylindrical envelope, an anode structure supported within saidenvelope intermediate the ends thereof and including a plurality ofcircumferentially displaced resonator structures, an end wall for saidenvelope including a pole piece having a frusto conical shape, a secondpole piece of frustoconical shape supported on the opposite side of saidanode structure and secured to the inner wall of said envelope, aclosure at the other end of said envelope including a concentricallylocated terminal and a sealing member interposed between said terminaland the wall of said envelope, and a conductor coupling said centralterminal with said anode structure and providing with the wall of saidenvelope a concentric transmission line section.

10. In an electric discharge device of the mag"- netron type comprisinga generally cylindrical envelope, an anode structure supported withinsaid envelope intermediate the ends thereof and including a plurality ofcircumferentially displaced resonator structures, a closure for one endof said envelope including a concentrically located terminal and asealing member interposed between said terminal and the Wall of saidenvelope, and a conductor coupling said central terminal with said anodestructure and providing with the wall of said envelope a concentrictransmission line section.

11. In an electric discharge device of the magnetron type comprising agenerally cylindrical envelope, an anode structure supported Within saidenvelope intermediate the ends thereof and including a plurality ofcircumferentially displaced resonator structures, a closure at one endof said envelope including a concentrically located terminal and asealing member interposed between said terminal and the wall of said en"velope and housed within said. envelope, and a conductor coupling saidcentral terminal with said anode structure and providing with the wallof said envelope a concentric transmission line section.

RICHARD B. NELSON.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 2,163,157 Samuel May 20, 19892,189,501 Helbig Feb. 6, 1940 2,411,299 Sloan Nov. 19, 1946 2,414,085Hartman Jan. 14, 1947 2,422,465 Bondley June 17, 1947 2,446,531 Derby'Aug. 10, 1948 2,485,401 McArthur Oct. 18, 1949 FOREIGN PATENTS NumberCountry Date 509,102 Great Britain July 11, 1939

